鄂尔多斯盆地东南缘岩溶热储对井回灌示踪试验

Reinjection tracer test of karst geothermal reservoir in the southeastern margin of Ordos Basin

回灌对维持地热储层压力、延长地热田寿命、保护生态环境具有重要的作用。鄂尔多斯盆地东南缘韩城地区广泛发育岩溶裂隙型地热资源,但其开发利用规模较小,为进一步评价该地区岩溶热储开发潜力,依托某地热工程,选取硫氰酸铵作为示踪剂开展对井回灌示踪试验,采用热突破模型预测长期回灌可能引起的开采井温度变化。结果表明,采灌井之间水力联系密切,有1个主通道与之直接相联,也可能存在其他次级通道。主通道上可能有溶潭发育,开采井温度100 a内下降了8.31℃,该对井回灌系统在服务期内未引起热储温度剧烈下降。

Reinjection plays a crucial role in maintaining the pressure of geothermal reservoirs,extending the lifespan of geothermal fields and preserving the environment.In the Hancheng area,located at the southeastern margin of the Ordos Basin in Shaanxi province,there is an abundance of karst geothermal resources.Despite this,the level of development and utilization of these resources in the region remains relatively limited.To further evaluate the development potential of Karst geothermal resources in the region,we implemented a karst geothermal heating project and conducting a tracer test,employing NH4SCN as the tracer.The goal was to establish an hydraulic connection between the production well and the reinjection well.Utilizing the thermal breakthrough model,predictions were made regarding the changes in the temperature of the production well as a consequence of long-term reinjection.The findings suggest that there is a primary direct pathway for the flow of water,and possibly a secondary path that may contribute to groundwater storage.The temperature of production well's water is projected to decline by 8.31℃over 100 years due to the reinjection process.However,this decline is not expected to cause a severe temperature drop in the geothermal reservoir within this dual-well system.